Vanadium steel alloy



Patented Mar. 12,19il0;

vANAnnnE STEEL ALLOY Vere B. Browne, Brackem-idge, Pa., assignor to Allegheny Steel Company, Breckenridge, Pa., a corporation of Pennsylvania No Drawing. Application January 2, 1930, Serial No. 417,927

4 Claims.

Chromium nickel steel alloys per se are well known and have high resistance to corrosion, except where the alloys are required to be heated to a temperature of around 500 to 900 C. without being subjected to a higher degree of heat, such as in welding. The consequences are that such alloys tend toward intercrystalline disintegration or deterioration unless annealed at temperatures several hundred degrees higher than said 500-900 C. temperature range. An annealing operation is not only inconvenient, and adds to the expense, but it distorts the alloy, especially if it has been provided with a particular shape or form so that further reshaping or straightening steps are necessitated.

I have as an object of this present invention the provision of an alloy and article thereof obviating and overcoming the difliculties and disadvantages of known alloys and presenting novel features and advantages peculiar to its own composition.

Another object of my invention is the provision of a chromium nickel steel alloy and article thereof containing vanadium, and having immunity to intercrystalline disintegration or deterioration.

I accordingly utilize what I have found to be an excellent chromium nickel steel alloy and to it I add predetermined amounts of vanadium.

As the art of alloying various metals is known in the industry, such needs no detailed consideration here and the process or steps involved form no part of this invention.

I may successfully use a chromium nickel steel of the following range of composition:

Per cent Chromium 6-40 Nickel .5-25

Carbon 0-.3 Iron Substantially entire balance tent may run from comparatively low percentages in the neighborhood of two or three percent to rather high percentagesaround 40, 50, 60, or even up to or 90%. Such compositions all have certain advantages but in general may be I said to be of somewhat limited use in such connections as would be calculatedto take advantage of the particular properties with which the different alloys were endowed by virtue of their composition. l

The range of about 640% chromium and .525% nickel is more convenient and more widely applicable in the industry, the particular composition of 18% chromium and 8% nickel being a particularly well known and useful one.

To such alloys, as I have above outlined, I add, at suitable points in the'production thereof, a predetermined amount of vanadium depending on the influence desired upon the ultimate prodnot. The presence of vanadium seems to endow the alloy with a particularly stubborn resistance to intercrystalline disintegration and deterioration and thereis probably a combined chemical and physical interaction resulting partly in the formation of new chemical compounds 35 and partly in the formation of solid solutions. Whatever the actual or theoretical correlation of the constituents, a new-alloy is evolved by the invention having the advantages set forth and others besides from which useful articles in the 30 chemical, metallurgical and physical fields can be made. I The amount of vanadium added is predetermined according to the results preferred in the ultimate product and hence may range from practically zero to several percent, or relatively large percentages, depending, too in a measureupon the intended use of the particular alloy and hence limited to some extent by the economics of the situation in question. A preferred (0 range extends from say .2% to 2 or 3%, but these figures are purely illustrative and variable according to circumstances.

Utilizing the chromium nickel steel set forth hereinabove and adding to it predetermined d6 amounts of vanadium according to the present invention, the following composition is obtained:

As exemplary of one successful alloy of useful a and advantageous composition, the following may be taken:

Such an alloy and hence an article made there: from is immunefrom intercrystalline or intergranular disintegration and deterioration and admirably retains its characteristics and properties even in the presence of ordinarily destructive acids, salts and high temperatures, present either singly 'or together. The properties of the chromium nickel steels themselves, as to ductility and malleability, are not diminished but such properties are influenced and enhanced by the vanadium to give an alloy and article having desirable and admirable properties and characteristics.

The vanadium may be incorporated in its isolated elemental state or in the form of one of its salts, compounds, or ores, due allowance being made for the combined or associated elements, and, in each case, a form being selected which introduces no undesirable substance into the alloy.

' Various modifications in the proportions of the constituents may be made without departing from the spirit and scope oi the principles above included.

What I claim as new and desire to secure by Letters Patent is: r

1. Metal articles which in their normal use are subjected to active corrosive influences while the metal in at least a part of the article is in a condition resulting from non-sudden cooling from temperatures within the chromium carbide precipitation range, said articles being resistant to intergranular corrosive attack and being composed of an austenitic chromium-nickel-steel alloy in which the chromium is present to the extent of approximately 18 to 25% and the nickel is present tothe extent of approximately '7 to 12%, the balance being principally iron, a small proportion of carbon, and vanadium, the vanadium and carbon being present in the alloy in such proportions and relation to each other that practically the whole of said carbon in said alloy appears therein in stable combination with m vanadium.

2. Metal articles which in their normal use are subjected to active corrosive influences while the metal in at least a part of the article is in a condition resulting from non-sudden cooling of the chromium carbide precipitation range, welding or heating at ranges within the carbide precipitato the extent of approximately 18- to 25%, the

nickel is present to the extent of approximately '7 to. 12%, and the vanadium to the extent of approximately 0.5 to 2%, the balance being principally iron with a small proportion of carbon, the vanadium in the alloy being in such proportion with relation to the carbon in the alloy that practically the whole of said carbon in said alloy appears therein-in stable combination with the vanadium.

3. Metal articles which in their normal use are subjected to active corrosive influences while the metal in at least a part of the article is in a condition resulting from non-sudden'cooling within the carbide precipitation range of temperatures, welding or heating within the carbide precipitation range without subsequent heating to materially higher temperatures, said articles being resistant to such corrosive attack and being composed of an austenitic chromium nickel vanadium alloy steel containing approximately 18% chromium, approximately 8% nickel, approximately 0.5% vanadium and not more than about 0.14% carbon, the balance being principally iron and the carbon being substantially all in chemically combined form.

4. Metal articles which in their normal use are subjected to active corrosive influences while the metal in at least a part of the article is in a condition resulting from non-sudden cooling within the carbide precipitation range of temperatures, welding or heating within the carbide precipitation range without subsequent heating to materially higher temperatures, said articles being resistant to such corrosive attack and being composed of an austenitiochromium nickel vanadium alloy steel containing approximately 18% chromium, approximately 8% nickel, approximately 0.2-3% vanadium and approximately 0.07-.3%-

carbon, the balance being principally iron and the carbon being substantially all in chemically combined form.

VERE B. BROWN'E. 

